how to create a repository from a folder code example
Example 1: how to make a folder into git repo
$ git remote add origin git@github.com:username/new_repo
$ git push -u origin master
Example 2: turn a folder into a git repo
$ git filter-branch --prune-empty --subdirectory-filter FOLDER-NAME BRANCH-NAME
# Filter the specified branch in your directory and remove empty commits
> Rewrite 48dc599c80e20527ed902928085e7861e6b3cbe6 (89/89)
> Ref 'refs/heads/BRANCH-NAME' was rewritten